Gender Mind-Benders

Men can be jerks. Hey, don’t argue with me — I’m just reporting scientific fact.
And women who act a little, well, crazy sometimes? Brain scans now reveal why. As a general rule, science that bolsters sexist clichés should be shunned, but two studies that caught our eye this month hold out hope for healing.

clipart.comSerotonin plays a major role in gender differences.

Forgiveness is a subject Case Western Reserve University psychologist Julie Exline, PhD, knows well. She’s done seven studies on it, examining forgiveness in 1,400 undergrads. (Can 19-year-olds represent all of us? Hope not, but we’ll go with it.) In several of the studies, Exline asked subjects to recall when someone had offended them. Then she randomly divided them into two groups. One group went straight to how forgiving they felt. The other group took a detour into their own history of offending people.

All of Exline’s studies have shown that men tend to be less forgiving than women. They also revealed that when men envisioned their own wrongdoing, their vengefulness decreased and their willingness to forgive increased to equal that of women. Weirdly, women did not become more likely to bury the hatchet when reminded of their own mistakes. It just made them feel lousy. Exline didn’t set out to prove a gender stereotype and, in fact, found it aggravating. She says, “We kept trying to explain it away, but it kept repeating.”

New insights from Sweden may show a gender divide in the brain mechanics of depression, anxiety, and PMDD, or premenstrual dysphoric disorder, a bad PMS characterized by aggressive irritability. At the Karolinska Institute, Hristina Jovanovic, MD, scanned the brains of healthy men and women, and of women who have PMDD, then compared them. She found major differences in the supply of serotonin, a molecule that regulates many brain functions, including sleep and moods.

Women have 39% more receptors, or landing pads, for these mood-affecting molecules than men do, but 55% less of a protein that transports them. This may account for why women suffer twice as much anxiety and depression as men.

And women with PMDD had lower levels of serotonin receptors than healthy women. Since many drugs work by adjusting serotonin, manufacturers may need to take a closer look at gender differences in the way their pills work.